Melting furnace



July 3, 1928.

c. E. FRAZIER MELTING FURNACE Filed Aug. 4, 1926 2 Sheets-Sheet //VVE/VTOR July 3, 1928.

C. E. FRAZIER MELTING FURNACE Filed Aug. 4, 192

2 Sheets-Sheet 2 FIELIII.

WITNESKSIS & W

Patented July 3, 1928.

UNITED STATES CHAUNCEY E. FBAZIE B, WASHINGTON, PENNQYLVANIA.

MELTING FURNACE.

Application filed. August 4, 1926. Serial No. 127,004.

My invention relates to improvements in melting furnaces. I have ap lied it in the construction of glass-melting urnaces of the class particularly designated continuous tank furnaces, but it may be applied to what are known as day tanks, and to other furnaces as well, such, for instance, as those used for melting zinc and other metal s. The ob ects in view are simplicity, durability, and economy in operation; more particularly, economy in the distribution and utilization of heat.

A glass-melting furnace of the continuoustank class and embodying my invention is illustrated in the accompanying drawings.

Fig. I is a view of the furnace n horizontal section, on the plane indicated at I-I, Fig.

II. Fig. II is a view in vertical and longitudinal section, on the plane indicated at II-II, Fig. I. Fig. III is a view in vertical and transverse section, on the plane indicated at IIIIII, Fig. I.

This furnace is of general rectangular shape, with walls formed of refractory material. The lower portion of the space within the walls constitutes the tank (in the metal industry commonly termed the hearth); theupper portion, which when the furnace is in operation is commonly spoken of as the furnace chamber, is the space through which the gases stream, burning as they advance. At one en provision is made for charging into the tank the material to be melted and refined, and for projecting into the space above the stream of gas orother fuel. At the other end there is provision for withdrawing from the tank the melted and refined glass, and forearrying away the gaseous products of combustion.

This essentially rectangular furnace is, in the particular development of it with which I have to do, modified in form, and'instead of extending .in right-line direction from end to end, it is formed as two half furnaces, so to speak, arranged side by side, with a par.- tition wall between, and connected one to the other at one end, so that the traverse of the material and of the gaseous stream is in U- shaped course. These two furnace halves bear in the drawings the referencenumerals land 2, respectively, and the partition wall which separates thembears the numeral 7. The two furnace halves are in communication at the ri ht-hand end, as seen in Fi s. I and II. T e opening through which t e molten glasspasses through thepartition wall is indicated at 3, and the larger opening through which the gaseous flow is maintained is indicated at 4. At the left-hand end of the furnace half 1 are arranged the charging opening 5, through'which the material to be melted and refined is introduced, and the port 6, through which the stream of fuel is introduced. At the left-hand end of the furnace half 2, suitable provision is made for the withdrawal of the melted and refined glass and for the escape of the products of combustion. The furnace half 1 which is the intake half is commonly termed the melting chamber, and the furnace half 2 which is the delivery half is commonly termed the working chamber or refining chamber. Such a furnace I shall as a matter of brevity and convenience term a twin-furnace.

In the glass-making industry automatic machines are extensively used for making small articles of many sorts,-pa er wei hts for example, bulls-eyes for van t lighting, salt cellars and containers of many sorts, jars, bottles, and the like. The glass is melted and refined in tanks, and automatic feeders are commonly employed for conveying the melted and refined glass in proper quantities to the forming machines. It is essential to the successful operation of such machinery that in the course of continued operation the temperature of the glass be substantially uni orm; wide variations of temperature are disturbing. In the operation of furnaces of the sort and having the characteristics which I have indicated, the problem hitherto has been to maintain uniformit in the temperature of the glass as it is re ned and supplied to the feeding apparatus. Variation in conditions of normal furnace operation are such that the variations in temperature of the glass produced tend to be unduly great. Compensation for and correction of such variations have hitherto been'attem ted, but without complete success. Propose s hitherto have been made to vary and control the openings for the passageway of the stream of flame through the partition, from the melting chamber to the working chamber. The partition wall elsewhere than at the end has been made perforate, and removable elosures have been provided for such perforations, and by manipulation of such closures the stream of flame has been diverted more or less from its normal course. By such means temperature has indeed been varied ill chambers 1 and 2 of -the furnace.

and controlled, but with an incidental bad effect; the quality of the glass has been impaired, and rendered uneven and uncertain, and this failure of uniformity has been no less disturbin to machine operation and has resulted too in the production of articles which, apart from the matter of success of machine operation, are on the ground of quality not wholly acceptable to the trade. My invention consists in improvements in structure and in consequent method of operation, whereby without any disturbance of the refining operation I am able still to control temperatures and to bring the glass to the point of delivery, uniform in quality and at substantially unvarying temperature.

The first feature of my lnvention which I shall describe is found in the'construction of the partition wall 7 which divides the two Hitherto it has been known practice to construct this as a heat-insulating wall, so far as concerns its lower portion, the portion which divides the two bodies of molten glass which lie in the two portions of the tank; but so far as concerns the upper portion of the wall, the portion which divides the furnace chamber above, it has hitherto been deemed desirable that the partition be heat-conducting, and that, serving to guide the flow of the stream of flame, it afford in least practicable degree obstruction to the transmission of heat. In order to accomplish the ends which I have in view I make the upper portion of i this wall, as well as the lower, heat-insulating. To this end the wall 7 may conveniently be constructed as shown in the drawings; it is a double wall, built of the usual refractory materials, and containing a heat-insulating air space-8. I preferably elaborate the structure and increase still more the heat-insulating effect by providing any air inlet 9, opening to the space 8 within the partition wall, and at one end of the space, and by providing also an air exit 10 at the other end of the space. I provide further a suction fan 11, to draw a stream of air from the outer atmosphere through the space 8 in the partition wall.

Manifestly, in the operation of the furnace the air which flows in a stream through the space 8 will become heated, and the quantities of heat so carried from the furnace may be returned to the furnace again in the stream of combustible gases which enters the furnace chamber through ort 6. Suitable means for accomplishing t is are illustrated. A recuperator 12 is provided for heating gaseous fuel in preparation for its introduction to the furnace, and to this recuperator 12 the stream of hot air drawn by fan 11 from wall space 8 may be carried, to serve there as a heat-giving agent. Mani-- festly, in addition to the suction fan 11, or even in substitution for it, I may employ a llalower to drive a, stream of air through in- Having by such structure eliminated heat conduction through the partition wall to such degree that it ceases to be an appreciable factor in furnace operation, I provide means for varying the direct heating effect of the flame upon the whole body of glass within the furnace, so that without' disturbance of uniformity in the quality of the glass I may make compensation for those variations in practical conditions which otherwise would disturb. the 1.temperattire, and to bring the temperature without substantial variation to the degree desired.

At the ri ht-hand end of the melting chamber 1, fprovide an outlet port 14, and I provide a damper 15, by 'which the effective area of the port 15 may 'be varied at will. I connect the port 14 with a suitable stack or other draft-creating structure, and by such provision I am able as furnace operation progresses to divert from the'furnace chamber through port 14 a variable fraction of the flowing stream of heat affording gases. So much of the stream as is not so diverted will continue in normal course, through opening 4 in the partition wall and through the length of chamber 2, to the outlet port 18 of the furnace. A damper 17 may be arranged in the line of gaseous flow beyond port 18, and by correlation in the adjustment of the dampers l5 and 17 the heating conditions may be varied with great nicety.

It is desirable to conserve the heat of the gases escaping from the furnace, and to this end the passageway 16 from port 4A and passageway 19 from port 18. as well lead to recuperator 12. These passageways last named unite as they approach the recuperator in a single passageway 20, and into this passageway the flow of air from the space 8 conveniently makes delivery. I have not shown a stack, nor other means of maintaining flow through the recuperator, for means to that end are a well known possession of the art.

In operation the glass making materials are introduced to the tank at the intake end of the furnace and molten glass is delivered at the delivery end. The stream of gases entering at port 6 sweeps through the length of the furnace, burning as it advances, and passes out through port 18. Byivir tue of the heat-insulating provision described there is no disturbing transference of heat from one branch of the flowing stream through the partition wall and to the other branch. At an intermediate point in the normal course of stream flow and specifically at the downstream end of chamber 1 a portion and any desired portion of the stream may be diverted, carried out from the furnace chamber and rendered of no further direct effect inthe glass melting and glass refining op found in the two dampers 15 and 17, and.

manifestly by these means the portion diverted may range from zero to the whole volume of the stream. The operator following the progress of furnace operation and noting the tendencies to temperature variation in the finished glass, varies the positions of dampers 15 and 17 and so corrects such tendencies. And since the heating stream is maintained in normal relation to the advancing body of material under treatment, the normal uniformity of the melting and refining operation is not disturbed.

The heat carried from the furnace both by such stream of air as may flow from wall space 8 and by the streams of gas issuing through ports 14 and 18 is in the recuperator l2 rendered up, in substantial quantities at least, to the gaseous fuel supplied to the furnace.

The diversion of a portion of the flowing heat-giving gaseous stream through a port or ports in the partition wall, and the control of such port-s by movable stoppers is not forbidden. For the reasons already given I do not recommend this practice; however, if the furnace contain those features which I have described as embodying my invention, the accidental disturbing effects of such ports is less pronounced than otherwise is the case. I show in dotted lines in Fig. III such a port 21, provided with a removable stopper 22.

I claim as my invention:

1. A melting furnace of twin construction adapted to carry in its lower portionthe material under treatment and in its upper portion a heat-giving gaseous stream and including melting and working chambers arranged side by side, the said furnace being provided with a port at the downstream en ofthe melting chamber, and meansfor diverting through said port a portion of a gaseous stream flowing through the furnace.

2. A melting furnace of twin construction adapted to carry in its lower portion the material under treatment and in its upper portion a heat-giving gaseous stream and including melting and working chambers arranged side by side, the said furnace being provided with a fuel port and with a deliveryport for the gaseous products of combustion and being further provided at the downstream end of the melting ch; iber with a second delivery port, 8.110. means for varying the effective relative areas of the two delivery ports.

3. In a melting furnace of twin construction adapted to carry in its lower portion the material undertreatment and in its upper portion a heat-giving gaseous stream and including melting and working chambers arranged side by side, the said furnace be ing provided with a fuel port and with a delivery port for the gaseous products of combustion and being further provided at the downstream end of the melting chamber with a second delivery port, a recuperator for fuel in operative relation to the inlet port, passageways leading from the two delivery ports to said recuperator, and means for varying the effective relative areas of said passageways.

4. In a melting furnace of twin construc tion adapted to carry in its lower portion the material under treatment and in its upper portion a heat-giving gaseous stream and including melting and working chambers arranged side by side and separated by a partition wall, the said furnace being provided with a fuel port at one end and with a discharge port at the opposite end and being further provided at the downstream end of the melting chamber with a second discharge port, and the said partition wall being chambered internally, a recuperator for fuel in operative relation to said fuel port, a' pas sageway for gaseous flow from said second discharge port to said recuperator, and means for maintaining the flow of a gaseous stream through said chambered partition wall and to said passageway.

5. A melting furnace of twin construction adapted to carry in its lower portion the material under treatment and in its upper portion a heat-giving gaseous stream and includin melting and working chambers arranged side by side, the said furnace being provided with a fuel port and with a deliveryport for the gaseous products of combustion and being further provided with a second delivery port, and means for varying the effective area of said second delivery ort. p In testimony whereof I have hereunto set m hand.

. CHAUNCEY E. FRAZIER. 

